DeleteInputDeviceRequest function doesn't handle "virtual" devices well.
TightVNC libvnc.so module to X (which makes bare Xorg VNC capable) uses such
kind of devices.
Bare Xvnc (it is something like Xvfb) simply uses AddInputDevice &
RegisterDevice functions. Xvnc uses DeleteInputDeviceRequest from Xi/stubs.c
so everything works fine (now I see that DeleteInputDeviceRequest in
Xi/stubs.c should call RemoveDevice function, shouldn't it? :) )
Situation is quite different when you use libvnc.so module. It uses same
schema as Xvnc, so it simply calls AddInputDevice & RegisterDevice. Thus
device is created correctly. When server is terminated it calls
DeleteInputDeviceRequest (now from hw/xfree86/common/xf86Xinput.c) for each
device. Here is the difference - Xvnc calls DeleteInputDeviceRequest from
Xi/stubs.c as I wrote above. Thus Xorg gets sigsegv because "VNC" devices
don't have real input driver.
X.Org Bug 20087 <http://bugs.freedesktop.org/show_bug.cgi?id=20087>
[This isn't really a fix (libVNC should behave correctly) but not crashing the
server sounds like an improvement.]
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>